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From: Mike Christie <michael.christie@oracle.com>
To: martin.petersen@oracle.com, linux-scsi@vger.kernel.org,
	target-devel@vger.kernel.org, mst@redhat.com,
	jasowang@redhat.com, pbonzini@redhat.com, stefanha@redhat.com,
	virtualization@lists.linux-foundation.org
Subject: [PATCH 07/17] vhost scsi: support delayed IO vq creation
Date: Thu, 22 Oct 2020 00:34:53 +0000
Message-ID: <1603326903-27052-8-git-send-email-michael.christie@oracle.com> (raw)
In-Reply-To: <1603326903-27052-1-git-send-email-michael.christie@oracle.com>

Each vhost-scsi device will need a evt and ctl queue, but the number
of IO queues depends on whatever the user has configured in userspace.
This patch has vhost-scsi create the evt, ctl and one IO vq at device
open time. We then create the other IO vqs when userspace starts to
set them up. We still waste some mem on the vq and scsi vq structs,
but we don't waste mem on iovec related arrays and for later patches
we know which queues are used by the dev->nvqs value.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
---
 drivers/vhost/scsi.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index 5d412f1..ab1b656 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -1401,7 +1401,7 @@ static void vhost_scsi_flush(struct vhost_scsi *vs)
 	mutex_lock(&vs->dev.mutex);
 
 	/* Verify that ring has been setup correctly. */
-	for (index = 0; index < vs->dev.nvqs; ++index) {
+	for (index = 0; index < vs->dev.max_nvqs; ++index) {
 		/* Verify that ring has been setup correctly. */
 		if (!vhost_vq_access_ok(&vs->vqs[index].vq)) {
 			ret = -EFAULT;
@@ -1464,6 +1464,9 @@ static void vhost_scsi_flush(struct vhost_scsi *vs)
 		       sizeof(vs->vs_vhost_wwpn));
 		for (i = 0; i < VHOST_SCSI_MAX_VQ; i++) {
 			vq = &vs->vqs[i].vq;
+			if (!vq->initialized)
+				continue;
+
 			mutex_lock(&vq->mutex);
 			vhost_vq_set_backend(vq, vs_tpg);
 			vhost_vq_init_access(vq);
@@ -1503,7 +1506,7 @@ static void vhost_scsi_flush(struct vhost_scsi *vs)
 	mutex_lock(&vhost_scsi_mutex);
 	mutex_lock(&vs->dev.mutex);
 	/* Verify that ring has been setup correctly. */
-	for (index = 0; index < vs->dev.nvqs; ++index) {
+	for (index = 0; index < vs->dev.max_nvqs; ++index) {
 		if (!vhost_vq_access_ok(&vs->vqs[index].vq)) {
 			ret = -EFAULT;
 			goto err_dev;
@@ -1551,6 +1554,9 @@ static void vhost_scsi_flush(struct vhost_scsi *vs)
 	if (match) {
 		for (i = 0; i < VHOST_SCSI_MAX_VQ; i++) {
 			vq = &vs->vqs[i].vq;
+			if (!vq->initialized)
+				continue;
+
 			mutex_lock(&vq->mutex);
 			vhost_vq_set_backend(vq, NULL);
 			mutex_unlock(&vq->mutex);
@@ -1632,8 +1638,13 @@ static int vhost_scsi_open(struct inode *inode, struct file *f)
 		vqs[i] = &vs->vqs[i].vq;
 		vs->vqs[i].vq.handle_kick = vhost_scsi_handle_kick;
 	}
-	if (vhost_dev_init(&vs->dev, vqs, VHOST_SCSI_MAX_VQ, VHOST_SCSI_MAX_VQ,
-			   UIO_MAXIOV, VHOST_SCSI_WEIGHT, 0, true, NULL))
+
+	/*
+	 * We will always need the ctl, evt and at least 1 IO vq. Create more
+	 * IO vqs if userspace requests them.
+	 */
+	if (vhost_dev_init(&vs->dev, vqs, 3, VHOST_SCSI_MAX_VQ, UIO_MAXIOV,
+			   VHOST_SCSI_WEIGHT, 0, true, NULL))
 		goto err_dev_init;
 
 	vhost_scsi_init_inflight(vs, NULL);
-- 
1.8.3.1

  parent reply index

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-22  0:34 [PATCH 00/17 V3] vhost: fix scsi cmd handling and cgroup support Mike Christie
2020-10-22  0:34 ` [PATCH 01/17] vhost scsi: add lun parser helper Mike Christie
2020-10-26  3:33   ` Jason Wang
2020-10-22  0:34 ` [PATCH 02/17] vhost: remove work arg from vhost_work_flush Mike Christie
2020-10-22  0:51   ` Chaitanya Kulkarni
2020-10-22  0:34 ` [PATCH 03/17] vhost net: use goto error handling in open Mike Christie
2020-10-22  0:45   ` Chaitanya Kulkarni
2020-10-26  3:34   ` Jason Wang
2020-10-22  0:34 ` [PATCH 04/17] vhost: prep vhost_dev_init users to handle failures Mike Christie
2020-10-22  5:22   ` kernel test robot
2020-10-23 16:15   ` Mike Christie
2020-11-02  5:57   ` Jason Wang
2020-11-03 10:04   ` Dan Carpenter
2020-10-22  0:34 ` [PATCH 05/17] vhost: move vq iovec allocation to dev init time Mike Christie
2020-10-22  0:34 ` [PATCH 06/17] vhost: support delayed vq creation Mike Christie
2020-10-22  0:34 ` Mike Christie [this message]
2020-10-26  3:51   ` [PATCH 07/17] vhost scsi: support delayed IO " Jason Wang
2020-10-27  5:47     ` Mike Christie
2020-10-28  1:55       ` Jason Wang
2020-10-30  8:47       ` Michael S. Tsirkin
2020-10-30 16:30         ` Mike Christie
2020-10-30 17:26           ` Mike Christie
2020-11-01 22:06         ` Mike Christie
2020-11-02  6:36         ` Jason Wang
2020-11-02  6:49           ` Jason Wang
2020-11-02 16:19             ` Mike Christie
2020-10-22  0:34 ` [PATCH 08/17] vhost scsi: alloc cmds per vq instead of session Mike Christie
2020-10-22  0:34 ` [PATCH 09/17] vhost scsi: fix cmd completion race Mike Christie
2020-10-27 13:07   ` Maurizio Lombardi
2020-10-30  8:51   ` Michael S. Tsirkin
2020-10-30 16:04     ` Paolo Bonzini
2020-10-22  0:34 ` [PATCH 10/17] vhost scsi: Add support for LUN resets Mike Christie
2020-10-22  0:34 ` [PATCH 11/17] vhost scsi: remove extra flushes Mike Christie
2020-10-22  0:34 ` [PATCH 12/17] vhost poll: fix coding style Mike Christie
2020-10-22  0:39   ` Chaitanya Kulkarni
2020-10-22  0:34 ` [PATCH 13/17] vhost: support multiple worker threads Mike Christie
2020-10-22  0:35 ` [PATCH 14/17] vhost: poll support support multiple workers Mike Christie
2020-10-22  0:35 ` [PATCH 15/17] host: support delayed vq creation Mike Christie
2020-10-22  0:50   ` Mike Christie
2020-10-22  0:35 ` [PATCH 16/17] vhost scsi: multiple worker support Mike Christie
2020-10-22  0:35 ` [PATCH 17/17] vhost scsi: drop submission workqueue Mike Christie
2020-10-29 21:47 ` [PATCH 00/17 V3] vhost: fix scsi cmd handling and cgroup support Michael S. Tsirkin
2020-10-29 22:19   ` Mike Christie

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